Abstract: The carbon content of the residue from combustion of agricultural waste products and the fly ash content of the gaseous exhaust is controlled by regulated inflow of the combustion supporting air in a plurality of flow stream at different velocities to enhance fluidization of particulate feed in a bed being raked by a rotating sweep arm inducing radially outward movement of combustion residue into a collecting zone from which the residue enters a discharge duct. The particulate feed is dropped at location in the combustion chamber above the bed in alignment with the inflow stream of maximum velocity.

Abstract: The carbon content of the residue from combustion of agricultural waste products is controlled and the fly ash content of the gaseous exhaust minimized by utilizing a portion of the combustion supporting air to enhance fluidization of the waste products above a fixed bed while being agitated by a rotating sweep arm inducing radially outward movement toward a residue collecting zone from which a sweep arm paddle displaces the residue into a discharge duct. The waste product feed is conveyed at a uniform weight flow rate to a central location in the combustion chamber above the bed from which of the feed is dropped onto the bed.